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                Berkeley DB Command Line Utilities
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            <h2 class="title" style="clear: both"><a id="db_dump"></a>db_dump</h2>
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      <pre class="programlisting">db_dump [-klNpRrV] [-b blob_dir] [-d ahr]
    [-f output] [-h home] [-P password] [-s database] [-D bytes] file

db_dump [-kNpV] [-d ahr] [-f output] [-h home] -m database

db_dump185 [-p] [-f output] file  </pre>
      <p>
         The <span class="command"><strong>db_dump</strong></span> utility reads the database file <span class="bold"><strong>file</strong></span> and writes it to the standard output using
         a portable flat-text format understood by the 
         <a class="xref" href="db_load.html" title="db_load">db_load</a> utility.  The <span class="bold"><strong>file</strong></span> argument must be a file produced using the
         Berkeley DB library functions.
    </p>
      <p>
         The <span class="command"><strong>db_dump185</strong></span> utility is
         similar to the <span class="command"><strong>db_dump</strong></span> utility, except that it reads databases in the
         format used by Berkeley DB versions 1.85 and 1.86.
    </p>
      <p>
        The options are as follows:
    </p>
      <div class="itemizedlist">
        <ul type="disc">
          <li>
            <p>
                 <span class="bold"><strong>-b</strong></span>
            </p>
            <p>
                Specifies the directory where BLOB data is stored for the
                database you are dumping.
            </p>
          </li>
          <li>
            <p>
              <span class="bold"><strong>-d</strong></span>
            </p>
            <p>
                Dump the specified database in a format helpful for debugging the
                Berkeley DB library routines.  
            </p>
            <div class="itemizedlist">
              <ul type="circle">
                <li>
                  <p>
                        <span class="bold"><strong>a</strong></span>
                    </p>
                  <p>
                        Display all information. See also the 
                        <span class="bold"><strong>-D</strong></span> option.
                    </p>
                </li>
                <li>
                  <p>
                        <span class="bold"><strong>h</strong></span>
                    </p>
                  <p>
                        Display only page headers.
                    </p>
                </li>
                <li>
                  <p>
                        <span class="bold"><strong>r</strong></span>
                    </p>
                  <p>
                        Do not display the free-list or pages on the free list. This mode is used by
                        the recovery tests.
                    </p>
                </li>
              </ul>
            </div>
            <p>
                 <span class="bold"><strong>The output format of the <span class="bold"><strong>-d</strong></span> option is not standard and may change,
                 without notice, between releases of the Berkeley DB
                 library.</strong></span>
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-D</strong></span>
            </p>
            <p>
                Specifies the maximum number of bytes to dump for each
                key/data item found in the specified database. This option is
                only valid when
                <span class="bold"><strong>-da</strong></span> is also specified.
                This option overrides the value set for the "set_data_len"
                parameter in your DB_CONFIG file, if any.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-f</strong></span>
            </p>
            <p>
                 Write to the specified file instead
                 of to the standard output.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-h</strong></span>
            </p>
            <p>
                 Specify a home directory for the database environment; by default, the
                 current working directory is used.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-k</strong></span>
            </p>
            <p>
                Dump record numbers from Queue and Recno databases as keys.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-l</strong></span>
            </p>
            <p>
                List the databases stored in the file.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-m</strong></span>
            </p>
            <p>
                 Specify a named in-memory database to dump.
                 In this case the <span class="bold"><strong>file</strong></span> argument must be omitted.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-N</strong></span>
            </p>
            <p>
                 Do not acquire shared region mutexes while running.  Other problems,
                 such as potentially fatal errors in Berkeley DB, will be ignored as
                 well. This option is intended only for debugging errors, and should
                 not be used under any other circumstances.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-P</strong></span>
            </p>
            <p>
                 Specify an environment password.  Although Berkeley DB utilities
                 overwrite password strings as soon as possible, be aware there may be
                 a window of vulnerability on systems where unprivileged users can see
                 command-line arguments or where utilities are not able to overwrite
                 the memory containing the command-line arguments.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-p</strong></span>
            </p>
            <p>
                 If characters in either the key or data items are printing characters
                 (as defined by <span class="bold"><strong>isprint</strong></span>(3)), use
                 printing characters in <span class="bold"><strong>file</strong></span> to
                 represent them.  This option permits users to use standard text
                 editors and tools to modify the contents of databases.     
            </p>
            <p>
                 Note: different systems may have different notions about what
                 characters are considered <span class="emphasis"><em>printing characters</em></span>,
                 and databases dumped in this manner may be less portable to external
                 systems.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-R</strong></span>
            </p>
            <p>
                 Aggressively salvage data from a possibly corrupt file.  The <span class="bold"><strong>-R</strong></span> flag differs from the <span class="bold"><strong>-r</strong></span> option in that it will return all possible
                 data from the file at the risk of also returning already deleted or
                 otherwise nonsensical items.  Data dumped in this fashion will almost
                 certainly have to be edited by hand or other means before the data is
                 ready for reload into another database
            </p>
            <p>
                Note that this option causes the utility to verify the
                integrity of the database before performing the database
                dump. If this verification fails, the utility will exit
                with error return <code class="literal">DB_VERIFY_BAD</code> even
                though the database is successfully dumped. If you are
                dumping a database known to be corrupt, you can safely
                ignore a <code class="literal">DB_VERIFY_BAD</code> error return.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-r</strong></span>
            </p>
            <p>
                 Salvage data from a possibly corrupt file.  When used on a uncorrupted
                 database, this option should return equivalent data to a normal dump,
                 but most likely in a different order.
            </p>
            <p>
                Note that this option causes the utility to verify the
                integrity of the database before performing the database
                dump. If this verification fails, the utility will exit
                with error return <code class="literal">DB_VERIFY_BAD</code> even
                though the database is successfully dumped. If you are
                dumping a database known to be corrupt, you can safely
                ignore a <code class="literal">DB_VERIFY_BAD</code> error return.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-s</strong></span>
            </p>
            <p>
                 Specify a single database to dump.  If no database is specified, all
                 databases in the database file are dumped.
            </p>
          </li>
          <li>
            <p>
                 <span class="bold"><strong>-V</strong></span>
            </p>
            <p>
                 Write the library version number to the standard output, and exit.
            </p>
          </li>
        </ul>
      </div>
      <p>
         Dumping and reloading Hash databases that use user-defined hash
         functions will result in new databases that use the default hash
         function.  Although using the default hash function may not be optimal
         for the new database, it will continue to work correctly.
     </p>
      <p>
         Dumping and reloading Btree databases that use user-defined prefix or
         comparison functions will result in new databases that use the default
         prefix and comparison functions. <span class="bold"><strong>In this case,
         it is quite likely that the database will be damaged beyond repair
         permitting neither record storage or retrieval.</strong></span>
     </p>
      <p>
         The only available workaround for either case is to modify the sources
         for the <a class="xref" href="db_load.html" title="db_load">db_load</a> utility
         to load the database using the correct hash, prefix, and comparison
         functions.
     </p>
      <p>
         The <span class="command"><strong>db_dump185</strong></span> utility
         may not be available on your system because it is not always built
         when the Berkeley DB libraries and utilities are installed.  If you
         are unable to find it, see your system administrator for further
         information.
     </p>
      <p>
         The <span class="command"><strong>db_dump</strong></span> and <span class="command"><strong>db_dump185</strong></span> utility output
         formats are documented in the 
         <a href="../../programmer_reference/dumpload_format.html" class="olink">Dump Output Formats</a> 
         section of the Berkeley DB Reference Guide.
     </p>
      <p>
         The <span class="command"><strong>db_dump</strong></span> utility may be used with a Berkeley DB 
         environment (as described for the <span class="bold"><strong>-h</strong></span>
         option, the environment variable 
         <span class="bold"><strong>DB_HOME</strong></span>, or because the utility
         was run in a directory containing a Berkeley DB environment). 
         In order to avoid environment corruption when using a
         Berkeley DB environment, <span class="command"><strong>db_dump</strong></span> should always be given the chance to
         detach from the environment and exit gracefully.  To cause <span class="command"><strong>db_dump</strong></span> to
         release all environment resources and exit cleanly, send it an
         interrupt signal (SIGINT).
     </p>
      <p>
         Even when using a Berkeley DB database environment, the db_dump
         utility does not use any kind of database locking if it is invoked
         with the <span class="bold"><strong>-d</strong></span>, <span class="bold"><strong>-R</strong></span>, or <span class="bold"><strong>-r</strong></span>
         arguments.   If used with one of these arguments, the <span class="command"><strong>db_dump</strong></span> utility
         may only be safely run on databases that are not being modified by any
         other process; otherwise, the output may be corrupt.
     </p>
      <p>
         The <span class="command"><strong>db_dump</strong></span> utility exits 0 on success, and &gt;0 if an error occurs.
         Note that this utility might return <code class="literal">DB_VERIFY_BAD</code> if the
         <code class="literal">-R</code> or <code class="literal">-r</code> command line
         options are used. This indicates a corrupt database. However, the
         dump may still have been successful.
     </p>
      <p>
         The <span class="command"><strong>db_dump185</strong></span> utility
         exits 0 on success, and &gt;0 if an error occurs.
     </p>
      <div class="sect2" lang="en" xml:lang="en">
        <div class="titlepage">
          <div>
            <div>
              <h3 class="title"><a id="idp10652584"></a>Environment Variables</h3>
            </div>
          </div>
        </div>
        <div class="sect3" lang="en" xml:lang="en">
          <div class="titlepage">
            <div>
              <div>
                <h4 class="title"><a id="idp10652896"></a>DB_HOME</h4>
              </div>
            </div>
          </div>
          <p>
                  If the <span class="bold"><strong>-h</strong></span> option is not
                  specified and the environment variable DB_HOME is set, it
                  is used as the path of the database home, as described in
                  the <a class="xref" href="envopen.html" title="DbEnv::open()">DbEnv::open()</a> method.
             </p>
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